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What a rainy week!

August 18, 2017

What a rainy week!

Over the past week many parts of the state have reported rainfalls totaling over 5 inches. Thunderstorms over August 13-14 brought record-setting rainfall to some Minnesota communities, including: 3.75 inches at Montevideo; 3.00 inches at Alexandria; 2.20 inches at Windom; 2.04 inches at Long Prairie; and 1.38 inches at Grand Portage.

Then even heavier rains came over August 16-17 this week, along with a few tornadoes in Nicollet, Sibley, and Blue Earth Counties, all very short-lived. The rainfall in these thunderstorms was record-setting at many locations, even more so than the rains earlier in the week. Some of the new record amounts were:
8.12 inches at Redwood Falls (many flooded basements); 4.11 inches at Willmar; 3.98 inches at Vesta; 3.66 inches at Marshall; 3.57 inches at Montevideo; 3.18 inches at Melrose; 2.88 inches at Pokegama Dam; 2.73 inches at Lake City; 2.67 inches at Pipestone; 2.66 inches at Lakefield; and 2.49 inches at Pine River Dam. The 8.12 inches at Redwood Falls was a new statewide record for August 16th. The Redwood River at River Falls rose nearly 4 feet, while the Minnesota River at Montevideo rose over 6 feet in response to these heavy rains.

No hail reports were associated with these storms, but some thunderstorm associated winds damaged trees in McLeod, Renville, and Redwood Counties.

Redwood Falls with 11.15 inches of rain, and Montevideo with 9.98 inches have already recorded their wettest month of August in history, and there are still two weeks to go. More heavy rain is expected across the southern half of the state over August 20-21.

State Fair Time:

The Annual Minnesota State Fair will begin next Thursday, August 24th and run through Labor Day, September 4th. It appears that the beginning days of the Fair will be sunny and dry with cooler than normal temperatures, perhaps just in the 70s F. I will be at the MPR Booth (corner of Judson and Nelson on the fairgrounds) on two dates: Friday, August 25th at noon to record the TPT Almanac public affairs program with hosts Cathy Wurzer and Eric Eskola; and then again on August 29 (Tue) with host Tom Weber at 11am to broadcast the annual Minnesota Weather Quiz. Please stop by if you are at the Fair either of those days. For other MPR activities and events going on at the State Fair visit the MPR web site.

University of Minnesota Extension will be well represented at the State Fair as well, offering programs and visits with specialists and educators. For more information visit the Extension web site

Weekly Weather Potpourri:

NASA scientists reported this week that wildfires burning just west of the Greenland ice sheet and depositing a great deal of soot and ash on the ice. This may hasten further melting of the Greenland ice sheet for the balance of summer. It was also reported that at least one community in Greenland had dispatched some firefighters to investigate and perhaps even help suppress these fires, which are likely occurring in peatland landscapes.

NOAA reported that the month of July 2017 was the 10th warmest in history across the contiguous USA. In addition they report that the first seven months of 2017 (January through July) were the 2nd warmest in history for the contiguous 48 states, 3.2°F above the 20th Century average.

In related news, the Washington Post reported this week that Death Valley reported the hottest singular month in world history with a July 2017 mean temperature of 107.4 degrees F. This was over 5 degrees above normal for the month there. The extreme high temperature for the month was 127°F on the 7th, while the extreme low temperature was 89°F on the 5th and the 25th. On three nights the temperature never fell lower than 102 degrees F. Other western USA cities like Reno, NV and Salt Lake City, UT also reported their hottest month in history during July of 2017.

In this week’s Earth and Space Science News Sarah Witman reports on the value of expanded rain gauge deployment to help water resource planners better manage streamflow and other hydrologic attributes.

Twin Cities Almanac for August 18th:

The average MSP high temperature for this date is 80 degrees F (plus or minus 7 degrees F standard deviation), while the average low is 62 degrees F (plus or minus 7 degrees F standard deviation).

Average dew point for August 18th is 59°F; the maximum dew point on this date is 79°F in 1995; and the minimum dew point on this date is 36°F in 2004.

All-time state records for August 18th:

The all-time state high temperature for today's date is 107 degrees F at Browns Valley (Traverse County) in 1976; the all-time state low for today's date is 24 degrees F at Tower (St Louis County) in 1975. The all-time state record precipitation for this date is 5.78 inches at Artichoke Lake (Big Stone County) in 1935. No snow has fallen on this date.

Past Weather Features:

About 7:30 pm on August 18, 1907 an EF-2 tornado (winds around 135mph) passed near Maple Plain (Hennepin County) destroying 15 cottages on Lake Independence. It was on the ground for 20 miles, killing one person and injuring 15. A barn was destroyed killing five horses inside.

There was an autumn-like chill in the air on August 18, 1915. Some northern Minnesota communities reported frost, and in southern Minnesota at Caledonia (Houston County) the thermometer struggled to climb into the low 60s F.

Widespread frost was reported in northern Minnesota counties on August 18, 1975. At Roseau the morning low was 30 degrees F, and the afternoon sun only warmed the temperature into the upper 50s F, feeling more like October than August.

By far the warmest August 18th in history was in 1976 when 30 Minnesota communities saw the thermometer top 100 degrees F or higher. The temperature at Redwood Falls and Montevideo never dropped lower than 78 degrees F that day.

Persistent thunderstorms brought heavy rains to southern and western Minnesota over August 18-20, 1990. Many areas reported 3 to 6 inches of rainfall and flooded roads were common in Swift, Chippewa, and Kandiyohi Counties.

Outlook:

A mostly sunny weekend with high temperatures near average for this time of year. Then, there will be increasing cloudiness later on Sunday with a chance for showers and thunderstorms by Sunday night. The chance for showers will carry over into Monday with persistent cloudiness that may affect viewing of the eclipse. Cooler and drier will prevail for Tuesday through Thursday of next week.